The Tsarnaev brothers, suspects in the Boston bombings, are ethnic Chechens, stemming from a tribal society in which a code of honor and revenge plays a major role. As questions turn to motive, this code may be far more relevant than the brothers' views of Islam.

In this image taken from a video, Patimat Suleimanova, the aunt of Boston bomb suspects, speaks to The Associated Press in her home in the Russian city of Makhachkala, in Dagestan, April 22. Ms. Suleimanova says Tamerlan Tsarnaev struggled to find himself while trying to reconnect with his Chechen identity: He 'seemed to be more American' than Chechen and 'didn't fit into the Islamic world.'

Washington —
With one suspect in the Boston bombings dead and the other in the hospital, investigators are now focusing on motive. Why should two young immigrants who had been given a home in the United States attack the iconic Boston marathon? Were they motivated by a specific interpretation of Islam pushing them to acts of violence? Or was it the geopolitical machinations of al Qaeda or some other terror group seeking to continue their violent struggle against the US?

These important questions are being explored, but I suggest they will yield little. An additional line of inquiry needs to be pursued that looks at the tribal background of Tamerlan Tsarnaev, who was killed in a shootout with police Friday, and his younger brother Dzhokhar. Both of them are ethnic Chechens, stemming from a tribal society in which a code of honor and revenge plays a significant role.

Consider this: The strike at Boston is, in all probability, the first terrorist attack in the United States in which the issues of tribalism and homegrown terrorism merged. True, 18 of the 19 hijackers on 9/11 had Yemeni tribal backgrounds. But they planned their attack from abroad. In contrast, other terrorists, such as Maj. Nidal Hasan at Fort Hood, were homegrown but did not have tribal backgrounds.

As an anthropologist, I’ve studied 40 remote tribal societies around the world, including in the Russian Republic of Chechnya, as part of my recent book, “The Thistle and the Drone: How America’s War on Terror Became a Global War on Tribal Islam.” Relations between the central government and tribal societies on the periphery range from indifference to outright hostility. The fiercely independent communities on the periphery feel the center is too inclined to use superior force to exploit their natural resources for its own purpose, threatens their customs, culture, and language, and pursues a policy of settling new immigrants in their lands in order to convert the local population into a minority.

While there can be no defense or justification for the alleged actions of the two suspects, without an understanding of their cultural or historical context it will be difficult to make sense of their motivation.

The Chechen people in the Caucasus region of Russia are a Muslim tribal people who have resisted Russian colonization of their lands for centuries. Like other tribal societies I studied, the Chechen are guided by a code of honor, in their case called nokhchalla. The code emphasizes courage, hospitality, revenge, and the protection of women. Each member of the tribe is linked to another and descended from a common ancestor. While Islam is part of their identity, it is Chechen tribal identity which defines them.

Nokhchalla, Islam, and traditional tribal life have been hammered by Russia over the last century. The two Boston terrorist suspects were from the Tsarnaev clan of the village of Chiri-Yurt in Chechnya. The Tsarnaev clan was, like so many other Chechens, forcibly moved to Kyrgyzstan by Stalin in the 1940s and lived in Tokmok near the Kazakh border. Most of the clan returned to Chiri-Yurt in the late 1960s. Yet three decades later, the people of Chiri-Yurt would find themselves embroiled in a savage war following Chechnya’s declaration of independence from Russia.

In 2000, the Russian journalist Anna Politkovskaya, who would later be assassinated, asked a village leader in Chiri-Yurt what the villagers wanted, as recounted in her book “A Dirty War: A Russian Reporter in Chechnya.” He responded, "People are in such despair...What did people dream of in the concentration camps?...Each village today is a concentration camp."

The suspects’ family fled the wars in Chechnya to Kyrgyzstan, and the youngest brother was born in Tokmok in 1993. From there they reportedly moved to Chechnya, then to Dagestan, and finally immigrated to the United States.

The two suspects arrived in the US as refugees about a decade ago, one still a boy, the other, a teenager. They had fresh memories of disruption, and emerged from a region in which Chechnya had witnessed genocide in the 1990s. By the end of the decade, the slaughter had resulted in the deaths of about 10 percent of the entire Chechen population and the displacement of one-third.

The scale of the killing and its brutality caused a distinct mutation of nokhchalla, emphasizing revenge and resulting in the tragic assaults by Chechen terrorists on the Beslan School, the Moscow Theater, and the Moscow metro. The same phenomenon can be seen among suicide bombers in the Tribal Areas of Pakistan, by Al Shabab in Somalia, and by Boko Haram in West Africa. These groups say explicitly: Our aim is to cause pain to your loved ones so you know what we suffer.

Arriving in America, the Tsarnaev family found themselves suspended between two worlds, disconnected from their old home and not quite fitting into their new one. Their own words reflect the isolation, pain, and anger they felt feeling rejected by both the broader American community and the Muslim community. The older brother complained of having no American friends. On his Twitter feed, the younger brother spoke of Muslims in the mosque asking him questions about his Muslim status and when he had converted to Islam. As an ethnic Chechen, he would have found that offensive.

The disconnect and tribal code may well have been strengthened when the older brother, Tamerlan, returned to the Caucasus in 2012 for six months, staying with his father, who had moved back to Dagestan, another troubled tribal periphery in the Caucasus. During that time, Dagestan experienced (and still does) violent, fatal clashes between security forces and the local tribal population.

When Tamerlan returned to the US, his YouTube account adopted a more puritanical, religious flavor, according to media reports. But if it is a tribal code of revenge that chiefly motivated the suspects, then their purpose in the bombings would have been nothing more than to inflict maximum pain in the cruelest way, evidenced by the targeting of the marathon, which is an apolitical event in which all the people of Boston, whether black, white, Jewish, Muslim, or Christian, come together to celebrate a new season and a historic tradition.

In the long term, the answer to violence abroad in tribal societies in the Muslim world is for central governments, including Russia, to change the paradigm with which they treat the periphery, granting all of their citizens equal rights, respect, and dignity. Government officials and security forces posted on the periphery need to have some idea of local culture and custom. Most importantly they need to act honestly and ensure justice between clans.

Lineage elders and religious leaders in these regions have traditionally underwritten the stability and continuity of tribal life. They have overseen councils which ensure that disputes are resolved and conflict contained. Unfortunately, central government officials and local lineage and religious leaders are now barely functional in most tribal societies as a result of violence. Central government officials have become the target of suicide bombers. Without a slow but determined reconstruction of this three-part administrative structure, there is little hope of peace in the tribal territories in the Muslim world.

Here in the US, Muslim leaders – especially imams and community leaders – need to be vigilant and act as guides to young people. The young need to channel their energy and angst toward constructive projects. Non-Muslim Americans also need to avoid feeding into stereotypes of Muslims as intrinsically associated with terrorism, which also alienates young Muslims. America must not go down the same route that it took over a decade ago, which created a chasm between Muslims and non-Muslims.

The challenge is to make isolated communities feel part of a larger community, to fulfill the pluralism envisioned by the Founding Fathers of this great nation.